Electrostatic generator capable of rapid build up of potential



Dec. 31, 1957 2,818,513

N; FELICI ETAL ELECTROSTA-TIC GENERATOR CAPABLE OF RAPID BUILD-UP OFPOTENTIAL Filed March '7, 1955 Illa IN VENTOR)` NOEL FEL/Cl MARCEL P10/NT ATTORNEY United States Patent M ELECTROSFIIATIC GENERA-'IGR.CABBLE'iOF -RAPIDBUILDsUP .0F BOTEN'IIAL l Al`loel`e1i`elici VandMarcel -loint;-Gi-enobl'e',l France,` assgnors to Societe Anonyme" dievMachines Electrostatiques, Grenoble, France, a corporationx-ofrliran'ceApplicationMarcli .7, 19.55,.,SeriiilNo.l .492,4951

1Claims priority,- appliaon FitancefMarchfS, 1'954l .2l-Claims..(Cl;310..6);

rlheA invention .relates to `ame'lec'trostatic:maohinetzvvliich `iscapable vot-rapidlya developingsa predetermined potential.

istence of an electrostatic'ltieldbetween theseaelectrod'es.

*The invention ywill Abev described'f inv` 1 1an f embodiment 'thereofrwhich `is particularly' adapted Fforrthe excitationiof an electrostaticgeneratorfutilizing-a-conveyorfoff'insulatfing .material supported' infrelation; to anexcitingf or charging inductor memberfan'd 'anl ionizingclement iii-opposed sp aced relation to 'this inductorfmemb'erL formovement fof the conveyor 4'member andl the ionizing v element^ withrespect to each iother-with 'the conveyor `disposed A between theinductoremenrberand ithe-ionizingp'element.' The conveyor Amember inthe'y form `of va Wall "ofi insulating `material thus-movingbetweenfftheinductorimember and'f'the ionizermovesthroughthefield-'which is'producedf'in the 2,818 ,513 atented--Dec.` 31, 1957 ICC 2e posed Mwhich. ,mayY be lconnected'` to the exciterelectrodes of ranelectrostatic generator having-V an insulating. con-.veyort forv `excitation thereof.- Thisv priming orstartingelectrostatic generator is constructedI with a conductive inductor`member and also with a'conductive .conveyor member which arevmovedrelative'to each othertintoa-nd out of inductive relation to eachother. In1such-a machine; and-particularly in'one constructedinaccordance withtliednvention l.in the mannerto '-be described, becauseof.l residual `charges on the conductiveelernents fand `havin'g regardrtoithe disposition ofthese elementsin'greateror lessproximity to bodieswhich themselvesrare charged, ithe'build-'up of the potential at-theoutput orloadterminaief: thefmachine may be'sta'rte'd upon -initiatngfand `vcontinuingI the yrelative movement of th'e inductor and`tlrerconveyor members with respect toeafchotherycon.- .ductive'connections being provided between the conveyor andrth'e load terminalso that the charge at the developed potentialA carried by the conveyormay be delivered to '.the loadlterminal during the initial movement'offthe con- 'veyor andv the inductor relative to each other;l Therapidity of the build-up of the potential in Isucha machine -risa-functionof the inherent capability'of-'th'e ymachine to ydevelop 'acharge in suitable amount at asufliciently ele- Ivatedpotential. Thisrapidity is greaterfac'cordingas the space between' theinductorf'member'andthe ionizingiele- 40 nment when,V having`l'egardosthe ich'aracter "ofthe idie'lectric materialin'thisspace;'usually a`gas,- afpotential difference is developedbetweenthe'inductormembei' an'dfthe ionizing element sufficient'torefect'ionization'of'thecgase- `ous material in Athisfspace.-',The'ionsthus"developed'fare conducted ,across Vthe ionizedfspace`.tothe surfaceiofthe i conveyor wall'and are .carriedthereby;.inf'the'movement of v.the conveyor tota suitablecollectingjmeans which 'may compri-se a .second 'ionizingclementconnect-edfto lal load terminal of..l the machine. [Preferably asecondinductor member;` is jdisposedQ-in opposed'relation vto saidionizing element at theopposite side'gof the lWall,therefrornjto act asl aY screen for facilitating the collction, of Jthe ch`arge from theconveyor', and. the delivery thereof to. the4 load terminal."A

In.. such a machine utilizingmaconveyor offinsulati'ng material land'electrodes spaced ',romv the. ,respective surfaces thereof, 'it' is`necessary-in order to,'sta`rt th`e machine in operation that "therequired.A potential diffrence 'rst shall'fbe developed 4between the:excitingf'inductorfinem- 'ber and the exciting lionizing,element-Because the gasvof auxiliary-'devices,- includiiig `frictionalgenerating machinesfmay be Putilized;

Iii-accordance vwith f the invention f-an electrostatic f'genyeratorA4capable f ofi s rapid builddipzo itspotentialH-isopw.

capacity which it necessary tofch'arge in' order `toobtain theIdesir'edfpoteutial is reduced. i

It is an object of the-.iuventionto' provideainachine capable lofrapidbuild-iup of potential kan'do'f'furnishing chargesat 'this potential in'the desiredV amounts;

It is another object of the invention' to'p'rovidela machine' providingrapid build-up of potential'lsuitabl for l( :hargingand exciting anelectrostatic generator having ,a conveyor of insulating material.

`Itis a 'further object ofthe invention to provide V.an electrostaticmachine capablevof rapidi build-'up ofpotentialandconstructed so as tooccupy a small-espace `andof such restricted dimensions that it does`not increase materially'pthe space necessary forthe electrostaticgenerator wit-h which it is associated'to produce the priming ,for

starting excitation thereof. i

kItis an'additional object of the 'inventionr to provide anelectrostatickgenerator utilizing .conductive inductors 45 and conductiveconveyormembers 'in which the y,conveyor members are to a high degree influencedlonl-y by the-inductoi' members and the eiiect of`stray,capacitiesis-minimized.

.lItjis-an important object of theinvention to provide 50 anelectrostatic generator of. thisl typesuitable-ffor excitingan excitergenerator having a conveyor of @insulat- Yingmaterial Ywhich isconnectedy to -and 'exciteseaf main generatorfconstructed forignition-of internal` combustion engines, =particularly automotiveengines.

Itlis ra featurefof the invention that provisionwisrnade totakeadvantage to the'maximum ,possiblefof the volume ofthedielectricmaterial, including-a gas nndertpr'essur'e, whichrserves to insulate theconductive:inductorzmemlbersfand-the conductive conveyor membersbothfrom Aeach other-and from the surrounding andv supporting Jparts andv`to' accomplish this purpose inamachinewhich lis-fof simple andinexpensive construction. 'Ihesepurposesaie .accomplished byconstructing a machine with a plurality ofi inductor members, havingregard tothe requisiteinsulationoffthese members at their potentials, so'as toincrease vthe-number' of -cycles of commutation vaccomplished in:each'rcy'cle 'offm'ovement of the conveyors; In-a p'ra'cticfal machineordinarily these inductor members will"-bef1di`s`- posed-about lanaxis'of rotation about which the `conduc- ^tive1fconveyor members arerotated insuccession` into and outfof inductive relation to the inductor:members in suc- .-cession;"-

The cycle of commutation may be carried out with reversal of thepolarity of the charge carried by the conveyor when in inductiverelation to two different inductor members at different potentials andcarrying charges of opposite polarity. These inductor members may be atpotentials respectively above and below ground potential. Thiscommutation, however, may be carried out relative to a referencepotential which itselt` may be above or below ground potential. In thelatter case, within the scope of the invention one or the other of theinductor members may be at ground potential.

Another feature of the invention serves to secure the desired rapidbuild-up and to add to the eifect of the dielectric fluid in which theinductive parts operate relates to the disposition of the inductormembers in face to face relation to two faces of the conveyors in orderto increase the useful capacity of these conveyors with respect to theinductors and to diminish the parasite capacities existing between theconveyors and charged bodies other than the inductor members themselves.Especially in a Amachine of this type in which the conveyor members aredisposed in spaced relation about an axis of rotation, the inductormembers also being spaced about this axis, since these inductor membersand conveyor members are movable into and out of inductive relation toeach other by rotation of the conveyor members on the axis and since theinductor members have portions thereof disposed at both faces of theconveyor members, the conveyor members move through the space betweenthese portions which are elfective to shield the conveyor members fromparasite capacities throughout a very large part of the rotation of eachconveyor member about the axis of rotation.

To further aid in reducing the effect of the parasite capacities andmake more effective the inductive action of the inductor members withrespect to the conveyor members, these conveyors in the electrostaticgenerator of the invention are partially or entirely covered with asolid insulating matrial. Such insulating covering avoids the necessityof providing on each conveyor and on each surface thereof a highlypolished surface. Such covering may be accomplished by disposing theconveyor members in spaced relation to each other about the axis ofrotation and entirely within the material of the wall of insulatingmaterial of a rotor which is co-axial with and rotatable on the axis ofrotation. When so covered, either partially or completely, by theinsulating material of the rotor, the space between the rotor carryingthe conveyor members and the stator supporting the inductor members maybe reduced, thereby increasing the useful capacity between the conveyormembers and the inductor members while reducing or eliminating the riskof electrical discharge taking place between these members. The maxi'-mum benett thus may be obtained of the dielectric strength of thedielectric fluid, ordinarily a gas under pressure, that separates theinductive parts that are movable relative to each other. The increase ofthe useful capacity, moreover, decreases the relative iniiuence of theparasite capacities, that is to say, capacities existing between theconveyor and inductive parts other than the inductors.

The machine of the invention is constructed so that the dimensions ofthe conveyors and of the inductors,

t especially the relative dimensions that are parallel to the path ofmovement of the conveyors with respect to the veyor is connected to areference potential as this conf veyor and the inductor are moved out ofinductive relainductors, provide that a plurality of the conveyormernbers in the movement thereof between the portions of the inductormembersI are disposed in face to face relation to each inductor member.The inductor member has an extent parallel to the path of movement,particularly an arcuate extent about the axis of rotation of the rotor,which is greater than the extent parallel to the path of movement or tothe arcuate extent of a plurality of the conveyor members and the spaceor spaces therebetween.

Since in the preferred embodiment, as hereinafter further described, aconveyor is connected to each inductor as the conveyor and this inductorcome into face to face inductive relation to each other and the samecontion to each other, each conveyor may be shielded by the inductorwhen this inductor is of suitable form and the elfective capacitybetween the conveyor and the other members of the machine, except theinductor, may be maintained as small as possible.

In the machine of the invention the charge carried by the conveyor asthe conveyor leaves inductive relation to a given inductor is increasedin potential and is delivered to the next inductor member which may beconnected'r to one of the terminals of the load circuit. The capacity tobe charged exclusive of that of the load circuit is constituted by allbodies which emit lines of force toward the respective inductors orreceive lines of force from these inductors. It is important, in orderto accelerate the build-up of potential with concomitant ability of themachine to discharge a sufficient amount of charge, that the capacity tobe charged shall be diminished as much as possible. This purpose may beaccomplished by utilizing one or more of the means about to bedescribed.

The inductors of the machine are disposed as far as possible from allmembers which constitute parasite capacities, such as members which aregrounded, and the adjacent inductors, and all other bodies which arecarried'l at a potential different from that of the particular inductorexcept, of course, the conveyors which are in face` to face inductiverelation to this inductor. This purpose is further accomplished byproviding a large number of conveyors of reduced dimension, particularlyin the direction parallel to the path of movement of circumferentiallyabout the axis of rotation so as to reduce the capacity of each conveyorwith respect to the stray capacities and to reduce the number of linesof force between each conveyor and the inductors. Thus, in a givenlength of the path of movement of the conveyors with respect to theinductor members, or in a given rotation of a rotor carrying theconveyors and moving the conveyors into and out of inductive relation tothe inductor members in succession, a large number of conveyors aresuccessively brought into inductive relation to each inductor. In suchmovement into inductive relation with an inductor each conveyor of smalldimension is connected to such inductor. A large number of cycles ofcharge and discharge of the conveyor elements in a given period of timethus is made possible and the required increase of potential and thedesired build-up of charge on the respective inductors are accomplished.

In order to accomplish the charging of the conveyor elements at a givenpotential and the build-up of potential and discharging of theseconveyor elements to inductors that are at a different potential, aplurality of sets of inductors are disposed along the path of movementor about the axis of rotation of the rotor. These sets of inductorsoperate at diierent potentials. They operate at opposite polarities andat potentials which may be symmetrical with respect to ground potential,or one or the other sets of inductors may be connected to a referencepotential or to ground potential and the other set may operate at apotential above or below the reference or ground potential. Where thereference potential is ground potential the conveyor, as it is about toleave face to face relation to a given inductor, is connected to ground,thereby undergoing an abrupt change of polarity.

fof inductors and conveyors has been disclosed in the application ofFelici, Morel and Point, Serial No. 390,346, tiled November 5, 1953, itis utilized in the electrostatic generator of the invention inconnection with the construction above vre'fer-red'to which secures'.theconditions outlined'above which make possible the 'r'a'pid build-upof potential 'and1`charge which are particularly de'slrable for exciting..a generatorfhaving an insulatingconveyor.

bers, two sets in`th`e embodiment disclosed, are disposed ininterspersed:spacedrelation about tan axis of rotation. A set comprisinginductorsl isdiisplosed on'a diameter 'throughthe axis. The interspersedsetcomprising inductors'2 'is disposedon 'a'diarneter'at right'angles tothe diameter of 'set '1. The'in'ductors 1 and2lofth'e respective setseach are composedY of twopportionsdisposed at'opposite sides of'the wall3 of 'a`holl'ow' rotor, Fig. 2, the "wall 3 being supported by a web'35for rotation on `th'eaxisof rotation so as to move' the wall 3 throughthe `spacerbetween the two portions'of eachinductor memberjand` inspaced relation to these portions; Y

Therrotor 3'is of insulating material and carries'conveyor'me'mbers 4ofconductive material. In the embodi- Vment disclosedinFigs. `1 and 2eight conveyor members are disposed in spaced relation about the axisofrota'tion. These'conveyormembers areof arcuateformcircumferenti'al'ly"about the axis of rotation andare embedded'inthe insulating material of` the wall 3 so thatall surfaces 'ofthe-"conveyor members are covered "by lthe insulating material'of thewall.

The arcuate extent and the spacingof the conveyor members from eachother is suchl that a plurality-of the conveyor members are disposedbetween ythe two portions of each inductor `member in the posi- `tion ofthe rotor when the conveyor'members respectively are being discharged tothe inductor member and are being charged with a charge oppositeV inpolarity to that of this inductor to be conveyed to the adjacentinductor Vfrnernberin the manner generallytreferred to abovev uponrotation of the rotor 3 in the direction of the arrow,

'Fig'. 1.

As shownin-Fig. 2, the inductor members 2 are suplp'ort'c'ad'byaninsulating stator 5in which is formed a recess 17, `the two portionsofthe inductor 2 beingdisposed at-the opposed-facesV of the recess whichlextend along and` generally parallel to the wall 3 of the motor whichlcarries 'the conveyor members 4. Preferably the rotor wall.3 is ofhollow cylindrical form about the axis of rotation andwith the web 35 isof bell shape, Fig. 2,

randthe'recess 7 is formed as a continuous annular cylindrical *recessinthe stator 5, so that the rotor wall 3 may be'frotated within thisspace between the two portions of the inductor member 2. It will beunderstood that the section ofFig. 2 taken through inductor 2 in Fig. lis typical o-f the arrangement also of the portions of the otherinductor 2 and of each inductor member ofset 1;

also that the rotor 3 and the conveyors 4 in the rotation thereof becomedisposed in the different positions in rela- -tion to the two portionsof each other inductor member,

as shown in Figs. 1 and 2 and above described.

The two portions of each inductor shown diagramma-tically in-Fig. 1 areelectrically connected together by connections '9, so that these twoportions will be at the same polarity and potential. In this embodimentalso the vtwo-inductor members of each set are electrically connectedtogether by the respective connections 11 andv 13. The inductors 1` areassumed to be at positive potential 'andfthe inductors 2 are assumedto-be at negative po- .tentialtbutmay be at other'potentials andpolarities,

`Disposed'inispacedrelation about the axisofL rotation ne'ctinto arconductive :rinfgf'17 which-maybe connected to leave inductive relationto an inductor member'but isfstillat'least partially, and preferably isfully, in inductive'relation to this inductor member, the spring contact19 connected to this conveyor member, engages the fixed contact 15associatedwith .this inductor'member: The' charge vcarriedbythe.conveyormoving betweenthe two portions'of this inductor'memberbefore contact '19 reaches contact 15 is atthe same potential andkpolarity'as that of this inductor member. This Apolarity of the.conveyor is abruptly changed when" the Aspring contact`19` engagesthe'xed ,contact 15. l 'charge on'the conveyor isfat a'plus potential,this charge If the Awill `be transferred to ground and the. conveyorwill receive a negative charge from ground which will beretainedupon'fthe conveyor when,.upon further rotation of ithe'rotorinthe direction of the arrow, Fig. 1, contact ofithe spring contact19 withthe fixed contact 15 is'broken.

The `negative charge now carried by this conveyor,

.increasing Ain potential as the conveyor moves. out from betweenthe'two portions of the positively chargedlinductorjis delivered tothenext adjacent inductor mem- `berw'hich'isat'a negative potentialwhen'this conveyor 'memberbecomes disposedbetween the two portions ofthis adjacent inductor member. This is accomplished by engagement ofthe'spring contact 19 connected to this conveyor V'with a fixed stud orcontact 21 disposed for'such engagement and connected to the twoelectricallyconnected portions of this adjacent inductor member atnegative potential. A plurality of such xed kcontacts 21 is disposed, asshown in Fig. 1,` in interspersed'relation to thefixed contacts 1'5 andin proper relation to the respective inductor` members about the axis ofrotation, so that each conveyor member which is charged ata givenpolarity as itvleaves a given inductor. member is discharged to the nextinductor member at the same polarity as the conveyor member whenthisconveyor member moves into inductive relation to this adjacent inductormember. When the spring contact,19 is disengaged from the fixedcontact21, while the conveyor member is moving between the twoportionsof the inductor member at the. same polarity and potential, thecharge is retained on the conveyor andis discharged therefrom and acharge of opposite polarity is received by the conveyor when the springcontact engagesthe fixed contact 15 as this conveyor is about tomoveoutof inductive relationfto thissame inductor as .above mentioned.

The action which has been described takesplace with respect to eachinductor member for each conveyor member. Alternate inductor membersthereby become chargedat opposite polarities, each set of inductormembers in cooperation with the conveyor members constituting theexciting means for the other set of inductor members cooperating withthe conveyor members. In the particular embodiment disclosed in Figs. land 2, the generator generates a dilerence of potential of predeterminedamount between the negatively charged inductors and the positivelycharged inductors, these connected inductor members of the two sets ofinductor members constituting the terminals of the machine. It will beunderstood, however, that the potential and polarity of the ring 17 andthe contacts 15 connected thereto may be determined above or belowground potential, the 4potentials and polarities of the two sets of I.inductor members being correspondingly determined so that the potentialof the ring 17 and the contacts 15 is intermediate between thepotentials of the two sets of inductor members.

In order to meet the condition that the charge carried by the conveyorshall not be dissipated by sparking to an adjacent conductive body, itis desirable to dispose the contacts 21 in such a manner that eachconveyor is discharged to the respective inductors as soon as theconveyor has attained a potential approximating that of the inductorinto inductive relation to which the conveyor is moving and to providethat the contacts 19 shall not be disengaged from the lixed contacts 21before the conveyors are fully in face to face relation to therespective inductors.

When the machine has never been operated or has been idle for aconsiderable time, the residual difference of potential between themembers, even though not very great, is suflicient in the machine of theinvention for building up the potential and the charge.

The features which have been described generally in connection withFigs. 1 and 2 are embodied in a machine of practical form as shown inFigs. 3 and 4. In these four gures like parts so far as possible carrythe same reference numerals. The rotor 3 is generally of the same hollowcylindrical bell shape as in Fig. 2, this rotor being supported forrotation on a shaft 25 which may be supported in suitable bearings notshown. A large number of conveyor members 4 are embedded in the wall ofthe rotor 3, similarly to the embodiment of Fig. 1, in spaced relationto each other about the axis of rotation of the shaft 25. The stator 5provides a recess 7 having parallel cylindrical surfaces co-axial withthe axis of the shaft 25 and this stator extends about the free end ofthe cylindrical wall 3 of the rotor and about the ends of the conveyors4.

The inductors 1, 2 in the embodiment of Figs. 3 and 4 are of U shape insection in a radial plane through the axis of the shaft, the twoparallel leg portions of the U extending along the opposed surfaces ofthe recess in the direction parallel to the axis. These inductormembers, moreover, are of arcuate form with the two parallel arcuateportions extending about the axis of rotation and parallel to the wall 3of the rotor. The conveyor members 4 may be of arcuate form or, becauseof their limited peripheral extent about the axis of rotation, may bemore or less flat. Upon rotation of the rotor 3 the conveyors move insuccession between the two leg portions of each inductor member 1, 2. Inthe embodiment of Figs. 3 and 4, six inductor members constituting twosets each consisting of three inductor members are provided. In thisembodiment twenty-six conveyor members 4 are carried by the rotor inspaced relation to each other about the axis and are embedded in thewall 3 of the rotor. Having regard to the description of theelectrostatic action given in connection with Fig. 1 to elcct chargingof the respective sets of inductors and the change of polarity orpotential of the conveyors upon engagement with the fixed contacts 15,it will 4be understood that a very large number of such changes israpidly produced in the embodiment of Figs. 3 and 4 upon rotation of thetwenty-six conveyor members about the axis and passing alternatelybetween the portions of the inductor members of the two sets 1, 2 ofinductor members that are at different potentials or polarities.

In the embodiment of Figs. 3 and 4 the inductor inembers 1, 2 may beformed of one piece of metal bent into the U shape and as shown insection in Fig. 3. T he form of these metal members may be such as to itclosely to the respective annular surfaces of the recess 7. Eachinductor member is provided with a lug portion Z7 which extends upon theinclined or conical surface of the stator 5 as shown in Fig. 3. The endof this lug 2.7 is secured by a screw 29 tapped into the stator, thisscrew 29 also 8 holding in place a stationary contact 31 which isdisposed generally radially and above the lug 27 for engagement with acontact connected to each conveyor member.

The contact carried by the rotor and connected to the conveyor may beformed as a lug portion 33 of the conveyor member 4 which extendsinwardly with respect to the cylindrical wall 3 of the rotor and abovethe contact 31 in Fig. 3. This lug 33 may be disposed closely adjacentthe web 35 of the rotor which is supported by the hub 37 iitted on theshaft 25.

in the space between each lug 27 of the inductors an additionalstationary contact 39 is disposed and held in place by a screw 41threaded in the insulating stator 5. This screw also holds in engagementwith the contact 39 a connection 43 connecting each of the contacts 39in common to a metal ring 45 extending about the hub 37. This metal ringmay constitute a body at the reference potential, or for this purposemay, if desired, be connected to ground, so that the potentialsgenerated by the generator may be respectively above and below groundpotential.

In order to establish the alternate inductors 1, 2 at common potentials,the two sets being at dilerent potentials, a metal ring 51 extends aboutthe exterior of the stator 5 and is provided with connections 52 throughthe stator wall to alternate inductor members. A second ring 53similarly extending about the stator and disposed in spaced relationtoring 53 along the axis is connected by connection 54 to each of theother inductor members. In accordance with the diagrammatic showing inFig. l, the rings 51 and 53 may constitute the terminals of the machinerespectively at positive and negative potentials, or one or the other ofthese rings may be connected to a predetermined potential, for example,ground potential, the other constituting the other terminal of themachine at a different potential. In this case, the metal ring 45constitutes the body at the reference potential or may be connected to abody of sufficient capacity to serve the function of supplying andreceiving the charges when the contacts 33 carried by the rotor andconnected to the respective conveyor members 4 are brought intoengagement with the contacts 39.

The charge carried by a conveyor at the reference potential is increasedin potential as the conveyor moves clockwise in Fig. 4 from one inductorto the next and is delivered at the increased potential to a contact 31to charge this next inductor through the lug 27 which is connected tothis contact. The charge carried by this conveyor when the contact 33 isdisengaged from the contact 31 is retained on the conveyor in itsmovement between the two leg portions of the inductor, the conveyor thenbeing insulated from any contact until the contact 33 cornes intoengagement with the next contact 39 that is connected to the ring 45 atreference potential. In this position of contact, the polarity of thecharge carried by the conveyor is reversed if the reference potential isground, or a corresponding change in the potential is effected if thereference potential is different from ground. The conveyor, continuingits movement out from between the leg portions of this inductor, has thecharge thereon increased in potential until this conveyor is connectedto the next contact 31 which is connected to the next inductor member asthe conveyor enters between the legs of this next inductor member.

In the machine of the invention the increase of potential is very rapid.This result may be accomplished in a machine constructed in accordancewith the embodiment of Figs. 3 and 4 in which the length. of thecylindrical rotor 3 of insulating material is about 35 millimeters andthe diameter thereof is millimeters. In such a machine the potential maybe multiplied by 30 in each revolution of the rotor for a usefulcapacity of 20 picofarads. In two revolutions ofthe rotor the initialdifference of potential will be multiplied by about 900. Thismultiplication of potential proceeds until the .operating potential ofthe e ast-asis .I inachine .isreacl'iedfin .view of the capacities4provided .by

ytlieinductors..and. conveyors, .the effect of. the lparasitecapacitiesand theeectiveness of the dielectric. gas, preferably `at apressure .of several atmospheres, and the. effectiveness oftheinsulationof the rotor:3.enrobing the con- ,veyor-s. 4.

.As-..ab.ove.,.indicated, when thev reference potential .isgroundpotential, .which may be established when thering l45isconnectedto ground, vthe two terminals respectively,connected.to.thettwosets .of inductors supply twosymmetrieaLpotentials-t-.U and -U.'. If the interconnectionvrprovicled,by,thering ,45.sinsulated.froml ground and from other? parts.and. one. .of the..sets of..inductors yis.connected Inground,.thefother inductor will .supplya potentialof:

vfl-Zllor -.2U..depending uponthe .polarity at which start- 15' .ing 'of.themachine rtakes place.l

Ihefinventionmay beembodiedin othervforrns-of electrostaticgeneratorsfthan that .shown ein the drawingsand For example, aplurality-of walls-or lSupported forrotation .within respective recessesin-an insulating. stator, the inductor members having portionselectrically .,connected..and disposed at .the .opposed sur-.nitrogenand oxygen, hydrogen or other'gasesf. Liquid 30;*

insulating .materials .having a high., dielectric constant I*may Vbeused..as.,the 1dielectriczmaterial.` Insuch cases :theintsulatingtmaterial.enrobing theconveyors preferably should vhave,adielectric `constant equal .to or greater thanthatofthe,.dielec triciluid...v

We. :claim:

1. An electrostatic generator having a rotor rotatable ,on .aniaxisandnpnoviding a wall lof vinsula'tingematerial `extending.aboutand along.saidaxis andabout va hollow .spacewithinsaidwall, a plurality ofconductive conveyors carriedbytsaidwall inspaced relation to eachotherabout saidaxis land each :having .an .arcuate extentk about said axis.and ,each extending .along said axis; a conductive -inductormemberhaving twoY generally parallel portions. thereof each of arcuate formextending Icircumferentially about saidaxis andk in spaced relationto.and at.y opposite sides.:of.said wallof ksaid rotor and extending along,said Wallofsaid .rotor inthe direction `generally along lsaid-axis,said portions of said inductor member being ,disposedv for movement ofsaidconveyor members therebetween in succession into and `out ofinductive relationtosaid inductor member .in.,.the..rotation of saidrotor lon said -axis,.and means for.connectingsaid conductive conveyormembers insuccession tov areference potential .concomitantlvwith `the.mo,vement..of said conveyor members in a predeter 55S" mined inductive.relation to said inductor member.

`2.. An electrostatic-generator havingna rotor `rotatable onanaxis andproviding a wall of insulating material extending p about and ,alongsaid yaxis .and abouta hollowy spacewithinsaid wall, a plurality ofconductive convey- Orscarried by `.said wall in spaced relation to cachother about said axis. andeach having an arcuate extent about said axis`and .each .extending along said axis to providean .inductivesurface onsaid conveyors, a conductive inductor member having two generallyparallel portions there of eachtof arcuate form extendingcircurnferentially about saidtaxis and in spaced :relation to and atopposite sidesof said .wall of said rotor andextending along said.wallof said rotor in the direction generally along said axis, saidportions of said inductor member being disposedfor tmovement of saidconveyor members therebetween in succession into and out of inductiverelation to said inductor member in the rotation of said rotor on saidaxis, means for connecting said conductive conveyor members in .suc-"cession to a reference potential concomitantly with the movementoflsaid conveyor members out of inductive relation to said inductormember, a load terminal. of said generator, and means for connectingsaid conductive conveyor members in succession yto said load terminalconcomitantly with -thelmovement of said conveyor members into:inductive relation .to said inductor member. l

3. An .electrostatic generator as delined in claim 1 which comprises aplurality tof .said inductor members disposed in spaced relationVvto.each other about saidtaxis-.of .rotation for movement .offsai-d.conductive conveyormembers in..successionfintoandout of positionYbetween said generally 3 parallel ,portions of the .respective inductor:members V,in .,succession..v

.4. Anelectrostatiofgenera'tor as denedin` claim 1 in which said.portionseof-lsaid:inductor memberv have r.an arcuate-. extent not lessthan lthe far-cuate 1extent of a fplurality.offconsecutive.conveyonmembers and the spaces therebetween. v

5...-An-.electros-tatic generator asvdetined-in claim l `in which lsaid:conveyor-'members v are embedded` Ain the` insulatingemat'erialYof-saidfvvall of saidrotor so as tocover aasubstantialportion.of thesurface ofsaid conveyorrmem- 16. yAn:electrostatic@generatoras detinedinclaim. 5. in

vwh'ichsaid. conveyor members Aarefully embedded intsaid v.insulating.materialo said wall of said rotor so thatthe insulating.materiabcoversall of the surface of said conveyor rmembers;l

7. An electrostatic generator as dened in claim yl which comprises aplurality `of `-said inductor lmembers disposed `inspaCed relationcircumferentially about said axis.of-rotation offfsaid-rotorf, means'forchargingalternate-induc tor'tmembers tat `a-.given potential, meanstforchargingfthe 5 other inductor members at anotherfpotential differentfrom said given potential, and means :for lconnecting fsaidconveyorgjmembers in successiontoa reference, potential intermediatebetweensaidtgivenpotentialy and saidotherfpotenytialy.concomitantlyvwith movement ofAsa-id conveyors in succession out `of iinductive relation -to eaoh.inductor member.`

8. An electrostatic vgenerator comprising (a =rotor having a wall ofinsulating material extendingabout la,hollow spaeetwithinsaidtwall andabout and alongtantaxis "of rotation, means-for supporting saidrotor-fforv-rotationon:said `iwa'xis with theuhollow spacekwithinsaidwrotor open iat-.an

yend thereof; a conductive-inductor member having Al.asportion.ysupported within said hollow rotornadjacentthe inner peripheral surface-of `*said nwall 'and Aa portionsuppor'ted adjacent `.the exteriorperipheral surface `of fsaid'iwall, `a plurality of .conductivevconveyor members supported l'by said rotor` walliiin spacedfrelationv toeach `other about said axis` of rotation formovementxof-saidconveyormembers intsuccession'into and out ofinductive relation :to landbetween .saidf'portions of-said inductor member,4 said conveyor memberseach-havinganarcuate extentiper'ipherally about said-axis Vandwextendingalong'said axis,- said portions-tof saidinductor lmember being lofarcuate forml extending v.p er'ipherallyabout and along saidvaxisofrrotation generally 'parallel to said wallandbeingelectricallywconnectedftogether, meansk for, connecting said`conveyor members yin 'succession to said inductor member'concornitantly.withithe :movement of said .conveyor members into induotiverelation 'tosaid inductor member, `and-.means for connectingfsaid'conductiveconveyor members-1in succession to a reference potential-concomitantlywith movement of saidconveyor members out of inductive relation tov'said `.inductor member.

9. An electrostaticV generator as-defined in 'claim 8 which comprises. a.plurality of said inductor members disposed in spaced relation to eachother about said axis otrotation formovement of said conductive conveyormembers vin succession into and out of position between said parallelportions of the respective inductor members in succession, said meansfor connecting said conductive conveyor members in succession to areference potential comprising` a member at said reference potential towhich each conveyor member is connected as it moves out of inductiverelation to each inductor member.

l0. An electrostatic generator comprising a stator of insulatingmaterial providing an annular recess having opposed peripheral surfacesco-axial with and extending along an axis of rotation from an open endof said recess, a rotor of insulating material supported for rotation onsaid axis and having a Wall providing peripheral surfaces co-axial withand extending along said axis of rotation, said wall of said rotorprojecting into said recess at said open end thereof and being disposedwithin said recess of said stator in spaced relation to said peripheralsurfaces of said recess, a conductive inductor member supported by saidstator and having a portion adjacent a given peripheral surface of saidannular recess, a conductive conveyor member carried by said rotor wallfor movement of said conveyor member into and out of inductive relationto said conductive inductor member upon rotation of said rotor, saidportion of said inductor member having an arcuate extent along saidperipheral surface of said recess and having an extent along said axisof rotation to provide an inductive surface generally parallel to saidrotor wall, said conductive conveyor member having an arcuate extentabout said axis of rotation substantially less than the arcuate extentof said inductor member and having an extent along said axis to providean inductive surface generally parallel to said rotor Wall, a contactcarried by said rotor for rotation with said conveyor member about saidaxis of rotation and electrically connected to said conveyor member, acontact supported by said stator and electrically connected to a memberat a reference potential and engageable with said rotatable contact uponrotation of said rotor on said axis for conducting a charge between saidconveyor member and said member at said reference potential.

11. An electrostatic generator as defined in claim 10 which comprises acontact supported by said stator and connected to said conductiveinductor member and engageable in the rotation of said rotor with saidcontact carried by said rotor connected to said conveyor member forconducting a charge between said conveyor member and said inductormember.

12. An electrostatic generator as defined in claim 10, said contactcarried by said rotor and connected to said conveyor member beingdisposed inwardly toward said axis of rotation with respect to saidrotor wall, said contact supported by said stator being supported by aportion of said stator disposed inwardly with respect to the Wall lofsaid rotor toward said axis of rotation for engagement of said statorcontact with said rotor contact.

13. An electrostatic generator as defined in claim 10 in which saidmember at said reference potential comprises a ring extending about saidaxis of rotation and connected to said contact supported by said stator.

14. An electrostatic generator as defined in claim l in which saidinductor member has a second portion electrically connected to said irstportion and extending along the annular peripheral surface of saidrecess that is in opposed relation to said given peripheral surface ofsaid recess, the portion of said inductor member disposed inwardly withrespect to said wall of said rotor being electrically connected to acontact supported by said stator within the hollow space of said rotorfor engagement in the rotation of said rotor with said contact carriedby said rotor and connected to said conveyor member.

15. An electrostatic generator comprising a stator of insulatingmaterial providing an annular recess having opposed peripheral surfacesco-axial with and extending along an axis of rotation from an open endof said recess, a rotor of insulating material supported for rotation onsaid axis and having a wall providing peripheral surfaces co-axial withand extending along said axis of rotation, said wall of said rotorprojecting into said recess from said open end thereof and beingdisposed within said recess v'IIS of said stator in spaced relation tosaid peripheral surfaces of said recess, a plurality of conductiveinductor members supported by said stator in spaced relation to eachother about said axis of rotation, each of said inductor members beingdisposed within said recess and being of U shape in section in a radialplane through said axis of rotation, each of said inductor membershaving the leg portions of the U disposed adjacent the respectiveadjacent peripheral surfaces of said annular recess and with the portionconnecting said leg portions extending about an end of said rotordisposed within said recess, said leg portions having an arcuate extentperipherally along the respective peripheral surfaces of said recess andan extent along said axis of rotation to provide an inductive surface ofsaid inductor member generally parallel to said surfaces of said wall ofsaid rotor, a plurality of conductive conveyor members carried by saidrotor wall for movement of said conveyor members in succession into andout of inductive relation to said conductive inductor members inSuccession upon rotation of said rotor, said conductive conveyor memberseach having a substantial extent along said axis and an arcuate extentabout said axis of rotation substantially less than the arcuate extentof each of said inductor members, a plurality of contacts carried bysaid rotor for rotation with said conveyor members about said axis ofrotation and respectively electrically connected to said conveyormembers, a plurality of contacts supported by said stator respectivelyelectrically connected to said inductor members and disposed forengagement in succession by said contacts carried by said rotor insuccession in the rotation of said rotor on said axis, and contactscarried by said stator and connected to a common member at a referencepotential and disposed in positions intermediate between successivecontacts connected to said inductors for alternate engagement of saidcontacts carried by said rotor with stator contacts connected to saidinductor members and stator contacts connected to said common member.

16. An electrostatic generator as defined in claim 15, which comprises aconductive ring supported by said stator and electrically connected toalternate inductor members to establish said alternate inductor membersat a common potential, and a second conductive ring supported by saidstator and electrically connected to the other inductor members toestablish said other inductor members at another common potential.

17. An electrostatic generator comprising a conductive conveyorsupported for movement thereof in a circumferential path about an axisof rotation, said conveyor providing a surface extending along said axisand extending about said axis generally parallel to said path ofmovement, a plurality of conductive inductor members supported in spacedrelation to each other about said axis and each having two portionsrespectively disposed inwardly towards said axis and outwardly from saidaxis with respect to said circumferential path of movement, saidportions each providing a surface adjacent said path and extending alongsaid axis and extending about said axis generally parallel to said pathof movement, whereby said conveyor is rotated into and out of positionsof inductive relation to said inductor members in succession betweensaid two portions of each of said inductor members.

18. An electrostatic generator as dened in claim 17 in which the spacebetween consecutive inductor members is not substantially greater thanthe minimum space required to prevent discharge between consecutiveinductor members, the summation of the circumferential extents of saidinductor members being substantially equal to the difference between thefull circumference about said axis and the summation of said spacesbetween said inductor members required to prevent dischargetherebetween.

19. An electrostatic generator comprising a plurality of conductiveconveyors supported in spaced relation to each other along and formovement thereof in a circumferential path about an axis of rotation,said conveyors each providing a surface extending along said axis andextending about said axis generally parallel to said path of movement, aplurality of conductive inductor members supported in spaced relation toeach other about said axis and each having two portions respectivelydisposed inwardly towards said axis and outwardly from said axis withrespect to said circumferential path of movement, said portions eachproviding a surface adjacent said path and extending along said axis andextending about said axis generally parallel to said path of movement,whereby said conveyors in succession are rotated into and out ofpositions of inductive relation to said inductor members in successionbetween said two portions of each of said inductor members.

20. An electrostatic generator as defined in claim 19 in which thespaces between consecutive inductor members are sufficient to preventdischarge between said consecutive inductor members, the summation ofthe circumferential extents of said portions of said inductor members 14occupying the major portion of the full circumference about said axis.

2l. An electrostatic generator as defined in cl-aim 19 which comprisesmeans for connecting said conductive conveyors in succession to areference potential concomitantly with movement of said conveyors out ofinductive relation to the respective inductor members, and means forconnecting said conductive conveyors in succession to the respectiveinductor members concomitantly with said movement of said conveyors intoinductive relation to the respective inductor members.

References Cited in the le of this patent UNITED STATES PATENTS 883,846Wommelsdorf Apr. 7, 1908 2,530,193 Felici Nov. 14, 1950 2,610,994 Boschet al. Sept. 16, 1952

